[Gate-users] Sinogram Output

[COMTAT Claude]

Hi Arda,

 

According to your output, you have:

 

>> entering [GateToSinogram::RecordEndOfRun]

    Number of prompt coincidences for all ring combinations        276

      Number of true coincidences for all ring combinations          276

        Number of scattered coincidences for all ring combinations     113

      Number of random coincidences for all ring combinations        0

    Number of delayed coincidences for all ring combinations       0

    sinograms 1,1,1,0,0 written to the raw file yourSinogram_1.ima

    sinograms 1,1,1,1,0 written to the raw file yourSinogram_1_del.ima

    sinograms 1,1,1,4,0 written to the raw file yourSinogram_1_sct.ima

 >> leaving [GateToSinogram::RecordEndOfRun]

 

You should then have 276 events in yourSinogram_1.ima; 113 events in 

yourSinogram_1_sct.ima and 0 events in yourSinogram_1_del.ima. As a consequence, the majority of the sinogram bins are set to zero! According to your geometry:

 

    Number of crystals per crystal rings: 576

    Number of crystal rings:              32

    Number of radial sinogram bins:    288

    Number of azimuthal sinogram bins: 288

 

You have 288*288*32*32 = 84934656 bins per sinograms. At best, 3e-6 of them are non-zero. So, when you visualize your sinograms, it is very likely that you only see zeroes. 

 

The difference between the sinograms is explained in your output!

 

    Prompt coincidences are recorded in data = 0

    Delayed coincidences (if simulated) are recorded in data = 1

    True scattered coincidences (eventID1 = eventID2) are recorded in data = 4

 

    sinograms 1,1,1,0,0 written to the raw file yourSinogram_1.ima

    sinograms 1,1,1,1,0 written to the raw file yourSinogram_1_del.ima

    sinograms 1,1,1,4,0 written to the raw file yourSinogram_1_sct.ima

 

So, yourSinogram_1.ima for prompts, yourSinogram_1_del.ima for delayeds, and yourSinogram_1_sct.ima for scatters.

 

Claude

 

-----Message d'origine-----
De : gate-users-bounces at lists.healthgrid.org [mailto:gate-users-bounces at lists.healthgrid.org] De la part de arda
Envoyé : mercredi 2 juillet 2008 23:13
À : Gate-users at lists.healthgrid.org
Objet : [Gate-users] Sinogram Output

 

 Hello,

 I am a beginner in GATE. 

(CLHEP 2.0.3.1 / Geant4 9.0 / root 5.14 / gate3.1.2)

 

 I am trying to obtain sinogram data from "PET_Ecat_System.mac" example

and visualize them on IDL.  I read the  "yourSinogram_1.ima" and

"yourSinogram_1_del.ima" (both 162 Mb) data on IDL and the entire data

are zero.

 Attached the log file and the macro I used

 

1) Could you tell me what I am doing wrong ?

2) Also, what are the differences between "yourSinogram_1.ima",

"yourSinogram_1_del.ima" and "yourSinogram_1.sct.ima" output data. Which

one I need to use on IDL to read the actuall sinogram?

 

Thanks,

Arda

 

 

 

 

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